Liu applies pharmaceutical research to sprayer cleanout

Zhijun Liu, left, holds a container of a solubilizer solution in water, and post-doc researcher Yixuan Dong holds a length of rubber tubing typical of commercial spray equipment. It’s difficult to clean herbicide residues from the hoses because of the porosity. Photo by Rick Bogren

Herbicide residue that remains in spray equipment, even after triple rinsing, can pose problems, especially when the residue is from 2,4-D or dicamba and the next job is soybeans.

LSU AgCenter researcher Zhijun Liu has been working with solubilizers for years with pharmaceuticals. Now, he’s testing his solubilizers in agricultural spray equipment with the goal of improving the cleanout process.

The challenging issue is removing herbicide residue from nozzles, hoses, pipes and connectors — particularly if the residue dries before the cleanout process begins.

“Some herbicides, particularly 2,4-D and dicamba in their acid forms, do not readily dissolve in water,” Liu said. “Adding a solubilizer in the rinse will help remove more of the residue from the equipment.”

Liu’s solubility enhancement compounds have been shown to work well in medical arenas, so they should perform well in agricultural applications, he said.

“We aim to solubilize more residues and do a better job of cleaning the equipment,” he said. A bonus is that the compounds he’s already developed are food-grade, derived from plant materials. “They’re naturally occurring and environmentally friendly.”

Liu has identified five to eight compounds he believes will do the job with agricultural chemicals. “The preliminary tests show promise in the laboratory,” he said.

The program is in its initial stage, focusing on the chemistry of the herbicides and using instrument analysis to evaluate the effectiveness of the solubilizers.